S-P958-KR-18eTrac, Inc. AlaskaeTrac Inc.F007631Complete Coverage for areas A and C, Object Detection for area BVicinity of AnchorageAlaskaUnited States200002018David Neff, ACSM C.H.Support NMS2018-12-072018-12-082018-12-22Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUniversal Transverse Mercator (UTM)UTCPacific Hydrographic BranchAll times are UTC. The purpose of this survey is to update existing NOS nautical charts. F00763 will cover approximately 4 square nautical mile in the vincity of Anchorage, Alaska.ContractoreTrac Inc. conducted hydrographic survey operations near the Port of Alaska and the vinicty of Anchorage, AK. F00763 covers approximately 4 square nautical miles of survey area. 191 linear nautical miles were acquired during the survey. Survey was conducted within these limits between December 8, 2018 (DN342) and December 22, 2018 (DN356).61.25589150.232361.16137149.9323All data were acquired in accordance with the requirements in the Project Instructions and specifications set forth in the Hydrographic Survey Specifications and Deliverables 2018 Edition (HSSD 2018).The purpose of this survey is to update existing National Ocean Service (NOS) nautical charts.The entire survey is adequate to supersede previous data.Survey F00763 is accurate to International Hydrographic Organization (IHO) Order 1a as required per the HSSD 2018.Survey Coverage was in accordance with the requirements in the Project Instructions and HSSD 2018. Area A and area C of F00763 were surveyed to Complete Coverage with backscatter standards set forth in the HSSD 2018. Area B of F00763 was surveyed to Object Detection Coverage with backscatter standards set forth in the HSSD 2018. Note: There is a small coverage gap at the southeast corner of area B due to a sonar blowout. The coverage gap was not able to be retrieved due to ice impeding survey operations in the Cook Inlet.Survey Coverage of F00763 (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Survey_Coverage.PNGSurvey Coverage of Area A - Complete Coverage (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Survey_Coverage_AreaA.PNGSurvey Coverage of Area B - Object Detection (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Survey_Coverage_AreaB.PNGSurvey Coverage of Area C - Complete Coverage (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Survey_Coverage_AreaC.PNGSurvey Coverage Gap within Area B - Object Detection (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Survey_CoverageGap_AreaB.PNGplaceholderplaceholderGlacier Wind0150000000Resolution0161000001400176000001408.21000042018-12-082018-12-092018-12-102018-12-22Refer to the Data Acquisition and Processing Report (DAPR) for a complete description of data acquisition and processing systems, survey vessels, quality control procedures and data processing methods. Additional information to supplement sounding and survey data, and any deviations from the DAPR are discussed in the following sections.Glacier Wind19.83.7Resolution8.50.9The R/V Glacier Wind is a 19.8 meter steel tractor tug equipped with a custom in-haul multibeam pole mount. The R/V Resolution is a 8.5 meter aluminum catamaran equipped with a custom over-the-side (starboard) multibeam pole mount.R2Sonic2022MBESR2Sonic2020MBESR2SonicI2NSPositioning and Attitude SystemApplanixPOSMV 320 V5Positioning and Attitude SystemAMLBase.XSound Speed SystemNote: R/V Glacier Wind utilized a R2Sonic 2020 mulitbeam echosounder system, an AML Base.X for the sound speed system and an I2NS for the positioning system. R/V Resolution utilized a R2Sonic 2022 multibeam echosounder system, an AML Base.X for the sound speed system and a POSMV 320 V5 for the positioning system.A comparison of crossline mileage to mainscheme mileage yields a crossline percentage of 6.4% for area A, 8.14% for area B and 9.44% for area C; This is noted to be above the required 4%. A beam-to-beam statistical analysis was performed using the Cross Check tool in Qimera. A 1 meter Combined Uncertainty and Bathymetric Estimator (CUBE) weighted dynamic surface was created incorporating only the mainscheme lines and excluded crosslines. The Cross Check tool was used to perform the beam-by-beam comparison of the crossline data to the mainscheme surface. Comparisons showed excellent agreement, well above 95% of the allowable TVU for areas A and B. For area C, the comparison between crosslines and mainscheme lines yielded a 85.2% for the beam-to-beam statistical analysis. The reason the percentage is lower is do to migrating sandwaves in the region. Mainschene lines were collected on DN342 and DN343 and crosslines were collected on DN344. Areas with large and small sandwaves show movement between days. Areas with no sandwaves show excellent agreement between days. Following images of the histograms for the beam-to-beam analysis of each area, there are images of the small migrating sandwaves, large migrating andwaves, and an area with no sandwaves to show the comparison between days in area C. Lastly there is an image with all three types of seafloor within one cross section. Crossline 2018RE3440651 is the crossline imaged in all four images. Note: These surfaces were created for QC only and is not submitted as a surface deliverable. The beam-to-beam crossline comparison report generated through the Qimera Cross Check tool is included in Separates II. Below are histograms of the crossline comparison statistics showing IHO Order 1a compliance per beam.F00763 Crossline Comparison - Area A (1m)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Crosslines_A_Histogram.pngF00763 Crossline Comparison - Area B (1m)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Crosslines_B_Histogram.pngF00763 Crossline Comparison - Area C (1m)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Crosslines_C_Histogram.pngSmall Sandwave Movement between Mainscheme and Crosslines\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Crosslines_SmallSandwaves.PNGLarge Sandwave Movement between Mainscheme and Crosslines\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Crosslines_LargeSandwaves.PNGAreas with No Sandwave show Excellent Agreement between Mainscheme and Crosslines\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Crosslines_NoSandwaves.PNGCross section of sandwaves and no sandwaves between Mainscheme and Crosslines\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Crosslines_Sandwaves_NoSandwaves.PNGGlacier Wind0.500.025Resolution0.500.025Standard deviation and uncertainty layers of the Dynamic Surface were utilized during data processing to search for features, water column noise, and systematic errors. IHO Order 1a uncertainty specification was met by 100% of the nodes. The final Bathymetric Attributed Grid (BAG) surfaces' uncertainty was generated through the NOAA QC Tools and an image of the results is located below. For Area A of F00763 the following percentages represent the results of the TPU testing: Complete Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface in NOAA QC Tools) = 99.5+% of nodes are within the allowable TPU. Complete Coverage MBES (Finalized 2m CUBE weighted Dynamic Surface in NOAA QC Tools) = 99.5+% of nodes are within the allowable TPU. For Area B of F00763 the following percentages represent the results of the TPU testing: Object Detection Coverage (Finalized 50cm CUBE weighted Dynamic Surface in NOAA QC Tools) = 98% of nodes are within the allowable TPU. Object Detection Coverage (Finalized 1m CUBE weighted Dynamic Surface in NOAA QC Tools) = 99.5+% of nodes are within the allowable TPU. For Area C of F00763 the following percentages represent the results of the TPU testing: Complete Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface in NOAA QC Tools) = 99.5+% of nodes are within the allowable TPU. Complete Coverage MBES (Finalized 2m CUBE weighted Dynamic Surface in NOAA QC Tools) = 99.5+% of nodes are within the allowable TPU. Area A of F00763 Finalized 1m Complete Coverage MBES TPU Statistics (NOAA QC Tools)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_TPU_A_1m_NOAAQCTools.pngArea A of F00763 Finalized 2m Complete Coverage MBES TPU Statistics (NOAA QC Tools)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_TPU_A_2m_NOAAQCTools.pngArea B of F00763 Finalized 50cm Object Detection MBES TPU Statistics (NOAA QC Tools)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_TPU_B_50cm_NOAAQCTools.pngArea B of F00763 Finalized 1m Object Detection MBES TPU Statistics (NOAA QC Tools)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_TPU_B_1m_NOAAQCTools.pngArea C of F00763 Finalized 1m Complete Coverage MBES TPU Statistics (NOAA QC Tools)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_TPU_C_1m_NOAAQCTools.pngArea C of F00763 Finalized 2m Complete Coverage MBES TPU Statistics (NOAA QC Tools)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_TPU_C_2m_NOAAQCTools.pngSonar system quality control checks were conducted as detailed in the quality control section of the DAPR.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.None ExistThere were no other factors that affected corrections to soundings.SVP casts were generally taken every 2 hours. Ocassionally casts would exceed a 2 hour frequency, however would never exceed a 4 hour frequency. On R/V Glacier Wind and R/V Resolution casts were applied in QPS QINSy acquisition software at the time of the cast. Surface SVP measured at 1Hz was compared to surface speed from the current profile in realtime. If the surface velocity comparison was in excess of 2m/s at any time during survey operations, a new cast was taken. Surface sound speeds were compared in realtime and profile to profile for each cast on the vessel. Additionally, the processor reviewed profiles in Qimera to remove spurious readings within a cast, compare day-to-day casts, and to check distribution over the surveyed area, in order to better understand trends for efficient acquisition planning.All equipment and survey methods were used as detailed in the DAPR.Data Density EvaluationIn order to determine if the density of the data met the specified 5 soundings per node, data density was evaluated using DensityTrac in the AmiTrac program, developed in-house by eTrac Inc. Each finalized CUBE weighted dynamic surface's nodes were exported to a BBH file. The BBH file was then loaded into the DensityTrac program and density statistics were computed. For F00763 the following percentages represent the results of the density query: Area A - Complete Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface ) = 98.8102% of nodes are composed from at least 5 soundings. Area A - Complete Coverage MBES (Finalized 2m CUBE weighted Dynamic Surface ) = 99.7178% of nodes are composed from at least 5 soundings. Area B - Object Detection Coverage MBES (Finalized 50cm CUBE weighted Dynamic Surface ) = 98.6938% of nodes are composed from at least 5 soundings. Area B - Object Detection Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface ) = 99.5475% of nodes are composed from at least 5 soundings. Area C - Complete Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface ) = 98.5096% of nodes are composed from at least 5 soundings. Area C - Complete Coverage MBES (Finalized 2m CUBE weighted Dynamic Surface ) = 99.4595% of nodes are composed from at least 5 soundingsArea A of F00763 - Finalized 1m Complete Coverage MBES Density Distribution\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Density_AreaA_1m.PNGArea A of F00763 - Finalized 2m Complete Coverage MBES Density Distribution\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Density_AreaA_2m.PNGArea B of F00763 - Finalized 50cm Object Detection MBES Density Distribution\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Density_AreaB_50cm.PNGArea B of F00763 - Finalized 1m Object Detection MBES Density Distribution\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Density_AreaB_1m.PNGArea C of F00763 - Finalized 1m Complete Coverage MBES Density Distribution\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Density_AreaC_1m.PNGArea C of F00763 - Finalized 2m Complete Coverage MBES Density Distribution\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Density_AreaC_2m.PNGAll data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.Backscatter data were collected throughout the survey and are retained in the raw DB files. Every effort was made in the field to collect quality backscatter data while maintaining the primary mandate of high quality bathymetric data. While no processing or analysis of backscatter was required, eTrac Inc. verified coverage and general quality of the backscatter data collected. A beam intensity window was monitored in Qinsy during aquisiton to ensure backscatter data collection. Raw backscatter data were viewed in QPS FMGeocoder to further confirm collection criteria had been met. Shown below is an example of the unprocessed backscatter mosaic from F00763 area A, area B and area C.Raw backscatter from Area A of F00763\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Backscatter_A.PNGRaw backscatter from Area B of F00763\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Backscatter_B.PNGRaw backscatter from Area C of F00763\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Backscatter_C.PNGNo Feature Catalog was used. Qimera was used as the primary processing software, which included feature management.F00763_A_MB_1m_MLLW_FinalCUBE12.320NOAA_1mComplete MBESF00763_A_MB_2m_MLLW_FinalCUBE21825NOAA_2mComplete MBESF00763_B_MB_50cm_MLLW_FinalCUBE509.220NOAA_0.5mObject DetectionF00763_B_MB_1m_MLLW_FinalCUBE11841.3NOAA_1mObject DetectionF00763_C_MB_1m_MLLW_FinalCUBE1320NOAA_1mComplete MBESF00763_C_MB_2m_MLLW_FinalCUBE21823.3NOAA_2mComplete MBESArea A of F00763 Delivered CUBE weighted Dynamic Surface Coverage - 1m (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Surface_Coverage_A_1m.PNGArea A of F00763 Delivered CUBE weighted Dynamic Surface Coverage - 2m (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Surface_Coverage_A_2m.PNGArea B of F00763 Delivered CUBE weighted Dynamic Surface Coverage - 50cm (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Surface_Coverage_B_50cm.PNGArea B of F00763 Delivered CUBE weighted Dynamic Surface Coverage - 1m (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Surface_Coverage_B_1m.PNGArea C of F00763 Delivered CUBE weighted Dynamic Surface Coverage - 1m (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Surface_Coverage_C_1m.PNGArea C of F00763 Delivered CUBE weighted Dynamic Surface Coverage - 2m (scale in meters)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_Surface_Coverage_C_2m.PNGplaceholder... no discussion by contractorMean Lower Low WaterNorth American Datum of 1983 (NAD83)UTM Zone 5NSingle BaseANCHORAGETSEAA chart comparison was conducted for F00763 using Qimera and Caris HIPS and SIPS. Contours and soundings were compared against the largest scale ENC, US5AK16M, to accomplish the chart comparison. Contour Comparison Method: Using the 1 meter CUBE weighted Dynamic Surface for areas A and C and the 50 centimeter CUBE weighed Dynamic Surface for area B, the 12 foot, 18 foot, 30 foot and 60 foot contours were generated in Qimera and displayed against the charted contour. Additionally, the CUBE weighted Dynamic Surfaces were viewed by a custom color band range based on the contour intervals (12ft, 18ft, 30ft, 60ft). The results of the comparison are described below, followed by 1-2 images of each area. Sounding Comparison Method: Using the same 1m and 50cm CUBE weighted Dynamic surface, soundings were generated in Caris HIPS and SIPS. Soundings were displayed against the charted soundings and a visual comparison was made. The results of the comparison are described below, followed by 1-2 images of each area.US5AK16M50000252018-11-062018-11-06falseArea A - Contour Comparison Results: The 18 foot contour on the southern edge of F00763 has excellent agreement with the charted contour and differs approximately 0 to 70 feet shoreward and seaward. The 30 foot contour has excellent agreement with the charted contour and has receded shoreward approximately 0 to 90 feet. In the western region of the survey boundary, the 60 foot contour has receded shoreward approximately 70 to 700 feet. In the center region of the survey boundary, the 60 foot contour has receded shoreward 280 to 330 feet. In the eastern region of the survey boundary, the 60 foot contour generally agrees with the charted contour, except for the very eastern region where the 60 foot contour has receded approximately 365 feet from the charted contour. Area B - Contour Comparison Results: The 30 foot contour no longer exists within the survey boundary. The 60 foot contour in the southern region of the survey boundary generally agrees with the charted contours and has receded shoreward approximately 50 to 220 feet. There are two shoals distinguished by a 60 foot contour in the center region of the survey boundary. The eastern one typically agrees with the charted contour. The western one disagrees with the charted contour because it is charted as connecting with the southern 60 foot contour. There are two additional smaller shoals distinguished by a 60 foot contour on the western edge of the survey boundary. This disagrees with the charted contour in that region which shows a larger shoal that is lcoated 175 feet west. The 60 foot contour on the northern edge of the survey boundary has progressed north approximately 5 to 580 feet, except near the eastern edge where the 60 foot contour has receded south approximately 30 to 350 feet. Area C - Contour Comparison Results: There is a 12 foot contour by the northern edge of the survey that does not exist on the chart and is part of a shoal within the survey area. The 18 foot contour has expanded north approximately 300 to 1700 feet. The 30 foot contour in the western corner generally agrees with the charted contour. The 30 foot contour in the northern region has receded north along its eastern and southern edge approximately 500 to 1000 feet. Along the eastern edge of that 30 foot contour, it has progressed south approxiamtely 900 feet. The 60 foot contour along the southern edge of the survey boundary has progressed north approxiamtely 150 to 350 feet from the charted contour. The 60 foot contour along the western edge of the survey boundary had moved west approximately 250 to 1900 feet from the charted contour. Area A - Sounding Comparison Results: In areas where the contours have changed, as noted above, and where a feature was detected, soundings differ from the charted depths. In area A of F00763, soundings are generally in agreement within 1 to 5 feet of each other. Various soundings differ up to 15 feet, however these are typically areas with dynamic sandwaves. Depth differences are not biased in any particular direction to support a systematic error. Area B - Sounding Comparison Results: In areas where the contours have changed, as noted above,and where a feature was detected, soundings differ from the charted depths. In area B of F00763, soundings are generally in agreement within 1 to 5 feet of each other. Various soundings differ up to 15 feet, however these are typically areas with dynamic sandwaves. Depth differences are not biased in any particular direction to support a systematic error. Area C - Sounding Comparison Results: In areas where the contours have changed, as noted above,and where a feature was detected, soundings differ from the charted depths. In area C of F00763, soundings are generally in agreement within 1 to 5 feet of each other. Various soundings differ up to 15 feet, however these are typically areas with dynamic sandwaves. Depth differences are not biased in any particular direction to support a systematic error. Area A of F00763 Contour Comparison (US5AK16M)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_ContourComparison_A.PNGArea B of F00763 Contour Comparison (US5AK16M)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_ContourComparison_B.PNGArea C of F00763 Contour Comparison (US5AK16M)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_ContourComparison_C.PNGArea A of F00763 Sounding Comparison (US5AK16M)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_SoundingComparison_A.PNGArea B of F00763 Sounding Comparison (US5AK16M)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_SoundingComparison_B.PNGArea C of F00763 Sounding Comparison (US5AK16M)\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_SoundingComparison_C.PNGNo Maritime Boundary Points were assigned for this survey.There were 4 charted features and 1 charted sounding assigned to F00763. The assigned features are retained in the Final Feature File (FFF). The assigned sounding was not included in the FFF per the investigation requirements listed in the CSF. Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format 3XXX). Refer to the FFF for determinations and recommendations of each feature.There were 5 new, uncharted features found in F00763, and added to the Final Feature File (FFF). Each feature was given a unique identifier in the "userid" field of the .000 S-57 file (format 3XXX). Refer to the FFF for determinations and recommendations of each feature.5F00763_DtoN_012018-12-20F00763_DtoN_022018-12-20F00763_DtoN_032018-12-20F00763_DtoN_052018-12-20F00763_DtoN_062018-12-20There were 5 DtoNs found in F00763, and added to the Final Feature File (FFF). Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format F00763_DtoN_XX). Refer to the FFF for determinations and recomendations of each feature. Note: All DtoNs were included in the number of new, uncharted features within section D.1.5.No shoals or hazardous features exist for this survey.No channels exist for this survey.No bottom samples were assigned to this survey.Shoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.eTrac was contracted by USACE to perform a hydrographic survey in October 2018 in the vicinity of area C of F00763. A comparison was made between datasets in Qimera. An image of the difference surface between the October dataset and area C of F00763 is located below. In the difference surface, red represents accretion, blue represents erosion, and white represents agreement between the two surfaces. Example cross sections are provided following the surface images. The first cross section across the two areas is over hard material and bedrock, which shows excellent repeatability and agreement. The second cross section across the two areas is over soft transient material. Signficant accretion can be seen in the McKenzie Pt. area. The material in this section of the survey area has been observed to change signficantly within a single tide cycle.October 2018 versus December 2018\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_PriorSurvey_DifferenceSurface.PNGCross Section 1 over hard material\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_PriorSurvey_Profile1.PNGCross section 2 over soft material\N:\Project Files\NOAA_T0009_Alaska\REPORTING\DR\F00763\Support Files\F00763_PriorSurvey_Profile2.PNGPacific Hydrographic Branch notes that the hydrographic survey referenced in D.2.2 has not been through an NOS approved review process and the quality of the survey has not been determined.No Aids to navigation (ATONs) exist for this survey.No overhead features exist for this survey.No submarine features exist for this survey.No ferry routes or terminals exist for this survey.No platforms exist for this survey.No significant features exist for this survey.No present or planned construction or dredging exist within the survey limits.No new surveys or further investigations are recommended for this area.No new insets are recommended for this area.As Chief of Party, Field operations for this hydrographic survey were conducted under my direct supervision, with frequent personal checks of progress and adequacy. I have reviewed the attached survey data and reports.All field sheets, this Descriptive Report, and all accompanying records and data are approved. All records are forwarded for final review and processing to the Processing Branch.The survey data meets or exceeds requirements as set forth in the NOS Hydrographic Surveys and Specifications Deliverables Manual, Field Procedures Manual, Letter Instructions, and all HSD Technical Directives. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required with the exception of deficiencies noted in the Descriptive Report.David R. Neff, C.H.VP of Survey, eTrac Inc.2018-02-05